Larger-bodied species of decapod crustacean animals, such as crab, are typically processed for their high valued meat. In this respect, they have historically been butchered by hand, with the meat then extracted manually using shears or scissors and packaged for shipment. Crab have also often been packaged as pre-cooked clusters comprising the crab's legs, claws and shoulder meat, which are then sold for consumption in that form. Regardless of the form of the final product, because labour rates are extremely low in many Asian countries, manual processing has largely shifted over time from North American plants to those in low-wage countries. This has led to a loss of jobs in previous crab processing hot-spots like Newfoundland, Canada. Thus, in order to better compete, crab processors have developed various machines to assist in automating various steps in the process. In the result, today crab clusters are typically processed using both manual and semi-automated processing methods.
The conventional method for cluster production is referred to as butchering. In such a method, live crab are manually butchered and cleaned by a worker at one of a plurality of workstations at a butchering table. Shown in FIGS. 1A and 1B are simplified front and side views, respectively, of a butchering table 100 that is known in the art, while FIG. 1C shows a simplified perspective view of such a butchering table 100. FIG. 1D, on the other hand, shows a simplified front view of a crab 102 prior to butchering. For explanatory purposes, crab 102 has a “centre body portion” generally comprising a carapace or “cap” 106 (a protective shell located on the top of crab 102) and an underside or “belly” 108 (which is also a protective shell that is not as hard or rigid per se as the cap 106), as well as appendages 104, including claws, claw arms and shoulders 110 located above appendages 104. To butcher crab 102, a worker picks up crab 102 by its appendages, with one hand located proximate each of the crab's shoulders 110, and then plunges “belly” 108 of crab 102 onto a stationary anvil-like device 112 of butchering table 100, as shown in FIG. 1B, thereby effectively splitting crab 102 in half, into two clusters. Simultaneously, cap 106 is torn away from crab 102 and two crab clusters 116 are formed, as shown in FIG. 1E, with shoulder meat 118 attached thereto. Shoulder meat 118 of each cluster 116 is then simultaneously pushed onto a rotating brush 120 located on either side of the stationary anvil-like device 112 to clean each cluster 116 by, for example, removing the gut and gills (not shown) of crab 102. A semi-automated method for butchering crab is more fully detailed in U.S. Pat. No. 5,401,207 to Hicks and Therien. Chungha Machinery Co., Ltd. of Korea (CHAMCO) manufactures a machine that severs appendages from the shoulder of a crab by means of a vertically rotating blade that makes a blind cut based on where the appendages are manually placed on a conveyor belt. [see https://www.youtube.com/watch?v=KhHEwYKMtPc for instance]
At present, there is no known technology that can butcher a crab in a fully automated fashion, nor is there a single system that is sophisticated enough to butcher crab into a variety of different crab portions (some specific and non-limiting examples of which include centre body portions, clusters, individual shoulder meat, and individual legs and claws), without manual intervention. While there is some technology currently available for the semi-automatic production of crab portions, as discussed above, that technology lacks the flexibility to readily butcher crab into a variety of crab portions. Existing automated technology also lacks the precision needed to efficiently, accurately, and repeatedly create high quality crab products for successful commercial sale. It is for this reason that the majority of global crab products are processed in a manner that requires a significant amount of manual labour. Greater and more precise automation of crab processing is therefore highly desired, especially in areas where wages in the local crab industry are not competitive with those in low-wage Asian countries.
The present invention seeks to overcome some of the deficiencies in the prior art.